RFID technology allows identification data to be collected remotely, which provides a significant advantage in identifying articles, parcels or other items. To access identification data stored in an RFID transponder (commonly referred to as a “RFID tag” or “tag”), an RFID reader/encoder generates an energy field via a transmission beam to interrogate the RFID tag, and subsequently, to retrieve data stored in the RFID tag. The data received from the RFID tag is processed by a computer system to identify the item that is associated with the RFID tag. Due to its convenience and reliability, RFID technology has found a wide range of applications, including item tracking, item location, inventory assessment, etc.
However, complications may occur in the detection of RFID tags in monitored areas where the dimensions of the monitored area present RFID coverage challenges. To attempt to overcome these challenges, conventional RFID reader systems employ multiple RFID readers placed about the monitored area. Nevertheless, detection challenges persist due to the fixed transmission beams of the stationary RFID readers and to multipath which causes fluctuations and areas of weak signal strength in the monitored area. Moreover, if the items are randomly placed and oriented within the monitored area, the RFID tags (and the respective antennas) will be randomly oriented with respect to the fixed RFID readers. Random orientation may result in a weak responsive signal from the RFID tag and also promote polarization errors and other deficiencies in the signals returned from the RFID tag(s).
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.